Even if you’ve never heard of Yik Yak, you probably know someone who uses it. The app, which lets anyone post anonymous messages visible only to others nearby, has a massive following in university towns – enough to be valued between $300 to $400 million by investors, despite not being monetized right now.

Meanwhile, college administrations across America have tried to ban the app without much success (though it is completely blocked at middle and high schools).

You might have heard all this and more, but what does Yik Yak actually do? The best way to find out is to install the app, which runs on Android and iOS devices. If you’d rather not, here’s a quick rundown of how the app works.

It’s Local

When you open Yik Yak, you’ll see the most recent comments from people within a ten mile radius with you. That’s it.

There’s no way to filter the content by topic, or follow particular people: location is the only way that messages are sorted. Think of it as a digital bulletin board to leave notes on, or – probably more accurately – a digital bathroom door to scratch messages onto.

This is the main difference between Yik Yak and other social networks. On Facebook you share things with “friends”; on Twitter, with “followers”. There’s no concept like this in Yik Yak – instead, everything you post is visible to anyone nearby. Your physical location determines your network.

Depending on where you live, you might not see much – but if you live near a university, you’ll probably see a lot.

It’s Anonymous

There’s no registration for Yik Yak – you can’t even pick a username if you want to. Everything you say on the network is anonymous, and all you need to do to join the conversation is install the app.

This means people feel completely securing saying pretty much anything. Sometimes people are self-reflective in ways they probably wouldn’t be without anonymity.

There’s Voting

Users can vote local comments up and down, which is part of the reason people love posting: validation. There’s always been an appeal to scratching funny message on the bathroom door, but what if you could find out how many people liked that message? This psychology of the upvote is no small part of what motivates people to leave notes on Yik Yak.

Messages that get a massive number of upvotes end up on the “Best All Time Yaks” page, a huge ego boost for those who can manage it. There’s no public way for you to show this “yakarma” off, the network being anonymous, but the app itself does track your points for you.

It Can Be Kind Of Funny

The voting system means some people try hard to be funny. Most don’t succeed – the place is full of lame one-lines.

Still, the humour is a big reason people check the app regularly.

It Can Be Informative, Sometimes

Occasionally Yik Yak can go from an amusing diversion to actually being useful. If there’s something going on near you, from a traffic jam to a protest, there’s a good chance someone is commenting about it on there.

(There’s also a good chance you’ll see comments about dorm life, hangovers, and poop.)

It Can Be Gut-Wrenchingly Terrible

Unregulated anonymous comments do have their downside. There have been all kinds of bomb and shooting threats made using the network, leading in many cases to arrests –posts are anonymous so far as other users are concerned, but you’re never really anonymous onlineCan You Really Be Anonymous Online?Can You Really Be Anonymous Online?We all have things we'd rather not tell the world about. I think it's time we clear up a few things about anonymity online -- and answer once and for all, whether it's really possible.Read More and the app’s owners do cooperate with law enforcement.

This isn’t uncommon online, but the local aspect of Yik Yak means that horrible racist might be someone you know – uncomfortable to say the least. A recent episode of Gimlet media’s Reply All podcast shows what Yik Yak can be like at its worst, and it’s not pretty.

And people have, using the app to spread all kinds of rumours. NBC called Yik Yak the new home of cyberbulling. It got so bad at high and middle schools across America that school boards tried to ban the app – without much success, until the app’s makers stepped in.

You Can Look In On Other Places

You can only post and comment in your geographic area, but it’s possible to see what people are saying in other places. Just search for any university or city to start browsing.

If you’re wondering what people are your old college are talking about, this is a quick way to find out. Lori Rozsa of the New York Times, a mother, spied on life at her child’s college using this feature, another potential use.

If you’re a parent, the fact that you’re reading about Yik Yak now probably means college kids will stop using it soon. The pattern with anonymous message boards is that they die when too many people find out about them – sites like JuicyCampus came before, and and apps like Erodr are working hard to replace Yik Yak as we speak. There’s no doubt this cycle will continue, so don’t be confused if you’re hearing about another anonymous app entirely in a few months.

Do you think Yik Yak’s bad reputation is unfair? What are your favourite parts of the app? Leave your comments below if I’ve been unfair, it’s possible I’m just becoming old.

Justin Pot is a technology journalist based in Portland, Oregon. He loves technology, people and nature – and tries to enjoy all three whenever possible. You can chat with Justin on Twitter, right now.